The document outlines essential definitions and processes of surveying, emphasizing its importance in measuring distances, angles, and elevations for infrastructure projects. It categorizes surveying into types, classifications based on purpose and instruments, and describes basic measurements and methods for distance measurement. Additionally, it discusses potential errors in linear measurements and advancements in electronic distance measurement technology.

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Distance measurement
Definitions
• Surveying may be simply defined as the art of
making measurements. Surveying involves the
measurements of Distances, angles and
elevations.
• It also involves staking out the lines and grades
needed for the construction of buildings, roads,
dams, and other engineering structures.
• In addition to the field measurements, surveying
includes the computation of areas, volumes, and
the preparation of necessary maps and diagrams.

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Cont…
• More precisely, Surveying can be defined as the art and
Science of determining the relative positions of various
points on, above or below the surface of the earth.
• When we say the relative positions of points it means
that determining the relative positions of points in
reference to another point or reference point/station.
For example, Adama City is found at about 100
kilometers East of Addis Ababa . In this example, it is
obvious that the (relative position) location of Adama
city is described in reference to Addis Ababa and that of
Adama University is in reference to Adama City.
•

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Importance of Surveying
• Surveying plays an essential role in the
planning, design, layout and construction of
our physical environment and infrastructure.
• Roads, Bridges, Buildings, water supply
sewerage, drainage systems and many other
essential public works, projects could never be
built without surveying technology.
• in construction and land-use projects

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Cont…
• surveying process starts with the reconnaissance
survey
• establish the best sites for survey stations
• Collect the necessary data
• produce plans
• used for planning Engineering projects, marking
boundary corners or lines, computations of areas
& volumes
• After finalizing the design or detail drawing,
setting out will be done.

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Types of surveying /Primary Division of Surveying
Surveying is thus primarily divided in two types:
• Plane surveying
• Geodetic Surveying

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Classification of Surveying based on purpose/
Applications/method
• Control Surveying
• Cadastral Surveying
• Topographic Surveying
• Construction Surveying
• Route survey.
• Photorgrametric Surveying
• Hydrographic surveys
• Cartographic surveying
• City surveys
• Mine Surveys, Geological surveys, satellite surveys,
Astronomic

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Classification of Survey based on
Instruments used
• Chain Surveying : is the simplest type of surveying in
which only linear measurements are taken with a chain or
tape
• Compass surveying: In this type of surveying, the
horizontal angles are measured with the help of a
magnetic compass, in addition to the line or
measurements with a chain or a tape.
• Leveling: this is a type of survey in which a leveling
Instrument is used for determination of relative elevations
(levels) of various points on, above or below the surface of
the earth

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Units of measurements
• Basic metric units of Length:- the is unit of measurement for
length is the meter and is subdivided into millimeter (mm),
centimeter (cm), decimeter (dm) meter (m)& kilometer.
1cm = 10mm 1m = 10dm
1dm=
10cm 1km = 1000m
• Basic metric units of Area:- when the unit of length is multiplied by
the unit of length, the result is the unit of area which is expressed by
m2 .
1cm2
= 100mm2
1m2
= 100dm2
1dm2
= 100cm2
1km2
= 106
m2
• Basic metric units of Volume:- when a unit of length (m) is multiplied
by the unit of area, we get the unit of volume which is given by m3
.
1cm3
= 10mm3
1m3
= 10dm3
1dm3 =
10mm3
1km3
= 106
m3

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Plane Angular Measure
– Radian system: 1 full circle = 2π rad.
– Sexagesimal System: 1 full Circle = 3600
,10
= 60’, 1’
= 60’’
– Centisimal System: 1 full Circle = 4000
, 1g
= 100g
, 1g
= 10mg
• The relationship b/n these systems is given as
follows:
• 1 full circle = 2 π rad = 3600
= 4000

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Conversion
Example: 1. convert 370
57’15’’ in to grad and rad
Solution
A. 3600
= 4000
370
57’15’’ x 400 = 42.171g
370
57’15’’ = ? 3600
B. 3600
= 2πrd 370
57’15’’ x 2πrad = 0.662rad.
370
57’15’’ = ? 3600
2.Convert 50g
in to degree and rad
A. 3600
= 400g
50g
x3600
= 450
? = 50g
400g
B. 400g
= 2πrad 50g
x 2πrad = 0.785rad
50g
= ? 400g

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Basic Measurements in Surveying
• Horizontal distance
• Vertical Distance
• Horizontal Angles and
• Vertical Angles.

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Horizontal Distance
• distance between two points as the distance
measured between the points which are in a
horizontal plane, the plane which is
perpendicular to the vertical direction at a
point or direction of gravity at the points or
the horizontal projection of the slope distance
between points which are on a slopping
Ground.

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Con…
• Horizontal distance is the distance measured
between points which are in a horizontal plane
or the horizontal projection of the slope
distance between points on a sloping ground.
• The most common methods for measuring
horizontal distances include: pacing, stadia,
taping, and electronic distance measurement
(EDM).

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Tape Measurement
• Types of Tapes
The most common surveying tapes are made
of a steel ribbon of constant cross-section
bearing graduations at regular intervals.
Others are made of a steel alloy or of a
metallic or non metallic cloth. There is great
diversity of tapes with respect to lengths and
widths and manner of graduation

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Con…
• steel alloy tapes, known as Invar or Lovar,
have a coefficient of thermal expansion about
one thirtieth that of steel and are used when
the taping specification prescribe a high order
of accuracy.

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Instruments &Taping Accessories
1. TAPE:- a tape is an instrument, mostly graduated in meter,
decimeter and centimeter, used for measuring accurate
lengths. Measuring tapes can be classified depending up on
the material in their man facture.
Eg. Linen tape, steel tape, invar tape, synthetic tape…
2. ARROWS (Chain pins):- they are used to mark the position of
the ends of the tape on the ground.
3. PEGS :- Wooden pegs are used to mark the position of the
survey station or the end points of the survey line.
4. RANGING RODS: - the process of locating a number of points
on a long survey is called ranging. Ranging rods are used to
locate intermediate points such that these points lie on the
straight line joining the end stations.

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Cont…
5. PLUMB BOBS:- They are made up of metal
used for fixing range poles vertically, centering
surveying instruments, and transferring pts
from tape to ground station while measuring
distance over sloping ground.
6. OPTICAL SQUARE: - it is a useful instrument
often used in combination with tape surveys
for producing rectangular angles (100gon or
900
).

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Taping Accessories

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C0nt…
• Pegs
• Arrow
• Ranging rod or poles
• Tripod
• Plumb bob
• Optical Square

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Horizontal Distance over Level Ground
/Taping on level ground/
1. Lining In. The line to be measured should be marked at both ends and
2. Applying Tension. The rear end of a tape is held over the first point, while the forward
end is lined in.
3. Plumbing. Weeds, brush, obstacles and surface irregularities may make it undesirable
to lay a tape on the ground. Instead, the tape is held above ground in a horizontal
position.
4. Marking Tape Lengths. When the tape has been lined in properly, tension has been
applied and the rear field assistant is over the point, 'mark' is called out.
5. Reading the Tape and Recording the Distance. Accurate field work may be cancelled
by careless recording.

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The simplest taping operation is measuring over level ground
where the tape can be stretched out while fully supported by the
ground, as shown in figure

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b. Taping Horizontal Distance over sloping Ground
Consider two point A and B which are several tape lengths apart along a slope. The
horizontal distance between the two points can be measured by supporting the
tape at the two ends only, as shown in figure below, using the method called
tapping break
.

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Taping Slope Distance
2
2
h
s
d 


Where d is the horizontal distance, s is the slope
distance, and is h the difference in height
between the two end points .
.
S h
d

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C0nt…
• Note that the accuracy of the computed horizontal
distance d depends on the accuracy of measured slope
distances & on the accuracy of the height difference h.

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Horizontal measurement on uneven ground

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Errors in Linear measurements and their corrections
• Errors of measurements are of three kinds:
• 1. MISTKES- mistakes are errors that arise from inattention,
inexperience, carelessness and poor judgment or confusion in the mind
of the observer.
• 2. SYSTEMATIC ERRORS- they always follow some definite mathematical
or physical law, and a correction can be determined and applied.
• Eg. The error in the length of the steel tape due to change in
temperature is a systematic error.
• RANDOM (ACCIDENTAL) ERRORS:- are those which remain after
mistakes and systematic errors have been eliminated and are caused by
a combination of errors.
• represent the limit of precision in the determination of a value, i.e., due
to lack of perfection in the human eye.
• E.g. In measuring a distance with a scale tape marked in centimeters,
one has to estimate a distance of 5mm as 6mm or 4mm because the eye
cannot judge the exact division.

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COMMON ERRORS IN TAPING AND THEIR CORRECTION 1
1. Incorrect length of tape.
2. Temperature other than standard.
3. Inconsistent pull.
4. Sag.
5. Poor alignment.
6. Tape not horizontal.
7. Improper plumbing.
8. Faulty marking.
9. Incorrect reading or interpolation.

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Tape correction formulas

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Optical Methods
 In the case of horizontal line of sight, the horizontal
distance between the instrument at A and the staff at B
is computed by D=KS,where, K=100, S=staff intercept.

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Electronic Distance Measurement
• Electronic distance measurement (EDM),
introduced in the 1950s
• The EDM equipments which are commonly used
are mainly electronic or microwave systems and
electro-optical instruments.
• EDM instruments are manufactured for use with
theodolites and as integral or modular
components of total station instruments.

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Cont…
• Current EDM instruments use infrared light or
laser light.
• Microwave systems (now largely outdated) use a
receiver/transmitter at both ends of the
measured line, whereas infrared and laser
systems utilize a transmitter at one end of the
measured line and a reflecting prism at the other
end.